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Crawl Space Doors and Entryways

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Many homes in and around Knoxville, Tennessee, have crawl space vents and entryways, and unfortunately, many of them are uncovered. This can cause a huge amount of damage to a property over time. This is why many homeowners check for crawl space doors and vent covers when they move into a home. After all, it pays to be prepared. 

Your property’s crawl space is one of the most vulnerable and exposed parts of your home. Its placement at the bottom of your home and its status as a hub for all the vital systems in your home make it a weak spot for all kinds of damage. With that in mind, it is reasonable to ask why homes were built with crawl space vents, doors, and entryways in the first place. The answer is simple: We didn’t know about the stack effect back then. 

Crawlspace door installation

Why Crawl Space Doors and Entryways Need To Be Covered 

One of the biggest issues with some crawl spaces is that they were built with exterior ventilation and access points in place. Between the 1950s and 1990s, the installation of crawl space doors and vents was seen as best practice in the construction industry, because it was believed that they would increase airflow and prevent issues like dampness and humidity. 

We now know that they do increase airflow in the crawl space, and around a home as a whole, but this is not actually a good thing. Thanks to something called the stack effect, this does more harm than good for your home. 

What Is the Stack Effect? How Does It Work? 

crawl space stack effect

The stack effect is the name for a phenomenon that occurs at home with correlating ventilation points in both the highest and lowest reaches of its structure. Caused by the way that air reacts to changes in temperature, the stack effect creates a channel of moving air that passes through the home. This is why it is also sometimes called the chimney effect. 

That’s because of how temperature changes impact the pressure in your property. If your property has a neutral pressure level, the air should remain stable and consistent throughout your home. When the stack effect is at work, however, it will draw in cool or warm air from outside, depending on whether your HVAC is producing heated or chilled air. 

This has many different impacts on a home. Most notably, it impacts a property’s HVAC system and its ability to retain the heat or cold that this system is used to create. This causes an unstable and often uncomfortable environment, while also increasing the rate of wear and tear that the HVAC system experiences, thereby making avoidable breakdowns more likely. 

The Benefits of Proper Crawl Space Doors 

Crawl space vents are quite easy to deal with, thanks to the availability of durable, waterproof, weatherproof, and heat-resistant crawl space vent covers. Doors and entryways, however, are another matter entirely. It is much harder to effectively seal these access points while still allowing for them to be used as intended. 

In most cases, any doors will be better than the original ones that were installed at the time of the property’s construction. This is because most original crawl space doors were made of wood. These were fine at preventing unlawful entry, but even treated wood is not waterproof in any real sense. 

As such, crawl spaces with their original doors and entryways tend to be more susceptible to dampness. Replacing these doors with waterproof, weatherproof doors that form a tight seal provides many benefits that include: 

Lower Humidity 

If your crawl space doors and entryways always create a proper seal, the chance of relative humidity inside your home rising because of airflow will be seriously reduced. Likewise, well-fitting, weatherproof doors and entryways will prevent water from leaking into the crawl space during periods of heavy rainfall and storm. 

This will keep the relative humidity as low as possible and prevent a whole host of secondary and tertiary issues from forming. A property with lower humidity is also likely to be more comfortable for people who have underlying health conditions. 

Less Risk of Mold and Mildew 

A lower level of relative humidity hugely decreases the chances of fungal growth like mold, mildew, and wood rot. These substances can be very damaging in several ways. Mold, for example, can be very damaging to the health and well-being of anyone who comes into close contact with it for a few reasons. Black mold, for example, can cause skin rashes, infections, respiratory problems, headaches, and even dizziness, fainting, or seizures. 

Wood rot fungus, by contrast, is very rarely harmful to people but will have a significant impact on your home, causing damage to flooring, walls, and even wooden furnishings. By installing crawl space doors and keeping humidity low, you could protect your health and the structure of your home. 

Increased Energy Efficiency 

Humid homes are much harder to heat and cool than arid ones. As such, your HVAC system will work harder and consume more energy when a poorly fitting or damaged crawl space door lets moisture into your crawl space. This will make your home less energy-efficient and cause your energy bills to rise over time. 

If you upgrade your doors and entryways, however, and the relative humidity lowers in your home, you will find that your bills also lower slightly. A beneficial side effect of this is the lower rate of wear and tear on your HVAC system. This will expand its lifespan slightly. 

Stable Interior Climate 

Dampness and humidity will also destabilize the climate inside your home in several ways. As well as creating a slightly unhealthy and uncomfortable environment, the extra burden on your HVAC (and the stack effect) will make the temperature in your home hard to maintain. As such, you can expect fluctuations in temperature over time and in different areas of a home. 

When you install waterproof crawl space doors and entryways, you will reduce or eliminate the stack effect in your home, lower humidity, and create a more stable environment that is both more comfortable and healthier. 

Even the best crawl space doors cannot do all the work by themselves. A non-waterproofed crawl space will always be more vulnerable to dampness, humidity, and a host of other issues. As such, fully encapsulating or waterproofing your property is one of the best ways to protect your home. 

Waterproofing: An All-Around Solution to Dampness 

Waterproofing your crawl space is one of the best things you can do to protect your home from several different issues and problems. Encapsulation and waterproofing is an all-around process that goes far beyond upgrading your crawl space doors and entryways. While the process looks different for every crawl space, you can expect waterproofing to take four stages: 


Insulation is a huge part of waterproofing and encapsulation, but it has plenty of benefits that go beyond reducing dampness. Properly insulating your crawl space walls, floors, and any exposed pipes will reduce the likelihood of frozen pipes and stabilize the temperatures around your home very quickly. Insulation will also increase heat and cold retention. As such, insulating your crawl space will make the lower reaches of your home far more comfortable, if it is set over two floors, and will make the interior climate consistent if your home is set over a single floor. 


For many homes in and around Mobile, Alabama, waterproofing and encapsulation means installing and upgrading the property’s existing drainage options. Drainage matting is one example, but in many cases, more robust options like sump pump systems are needed to remove water from the area as it gathers. 

There are also exterior drainage options and modifications that can prevent foundation saturation and perimeter flooding. 

Vapor Barrier Installation 

Vapor or moisture barriers are an integral part of crawl space waterproofing and encapsulation. These products repel moisture and create a safe, dry, clean space within the crawl space, thereby stabilizing the environment in the property over time. This does nothing to repair damage but adds an extra layer of protection once repairs have been completed. 

Vapor barrier installation has an additional benefit that is often overlooked; if you install a heavy-duty 20-mil barrier that is resistant to tearing and puncturing, you can also use your crawl space as a storage area for seasonal items. 


In some homes controlling moisture is a much more intensive process that requires active dehumidification. Thankfully, dehumidifiers come in all shapes and sizes, now, and there is a model for every home and budget. If a professional deems dehumidification necessary, the installation of a dehumidifier will be the last step in any waterproofing and encapsulation process. 

Just be sure to get the right model for your home, as desiccant and refrigerant dehumidifiers are best suited to different environments. An expert will be able to provide you with guidance and help in this matter. 

If you notice signs of dampness and damage in your property, waterproofing could well be a huge part of the solution. You will have to deal with any damage separately, however, as waterproofing and encapsulating over damage will only cause more problems in the long run. 

Doors and Entryways


Waterproofing and encapsulation may seem like a straightforward process, but there are a number of things you must consider during this process. That means it’s best to seek professional help to avoid causing more damage to your home in the long run. 

Before Waterproofing 

Most of all, you need to consider the amount of work that will often need to be done before encapsulation can begin. Waterproofing is not a save all for your problems. It is better used as a preventative measure and should be installed into a space that is as healthy as it can be. This means that inspecting your property for signs of damage is the first step in any waterproofing process. 

Being able to identify co-occurring issues like dampness, humidity, mold formation, wood rot, and pest infestation is crucial, as all these issues must be dealt with before the crawl space can be safely waterproofed. Likewise, any structural damage should be fully resolved before you begin encapsulating this space. As a non-professional, there is simply no way you can be certain you have identified all of the underlying issues. There is also a limited likelihood that you will be able to rectify the problems that are present in your property. 

The Waterproofing Process 

Once structural damage has been repaired and all co-occurring issues have been resolved, there is still the matter of effectively and seamlessly encapsulating the space. Most parts of the waterproofing process are a little more complex than fitting a new crawl space door, and there is little room for error when doing something like vapor barrier installation, for example. Professionals have the skills and tools, but more importantly, the experience needed to do the job right in the confined space that a crawl space provides. 

Professionals also have access to the absolute best products and tools, because they can buy from professional supply stores (and even direct from the manufacturer where necessary). This means you can expect to get a better, more durable result from professional waterproofing than you could achieve on your own. Because of this, the real cost-effectiveness of professional work could be proportionally less than that of DIY. Fewer mistakes and a longer-lasting result can really make all the difference. So, while we understand the desire to save time and money, we urge you to call in an expert when it comes to crawl space waterproofing.  

Dampness is a common issue in crawl spaces across the U.S. for several reasons. While low-level dampness may be simply unpleasant, there are structural and health concerns that can come with serious, prolonged dampness in any home. 

Home Concerns 

Prolonged or serious dampness in any part of your home can have a significant impact on the health of your property in a few ways. Dampness can make your home colder, less comfortable, and create an unpleasant smell, but there is also the matter of fungal growth. More specifically, wood rot fungi have the capability to damage your floor, walls, and any other structure in your property that is made of wood. 

Wood rot comes in three main forms: brown rot, white rot, and soft rot. Each of these forms of wood rot looks slightly different, but they cause the same issue. They cause dead wood to decay. In nature, this is a helpful function, but in a home (where all wood is dead wood), it is a very worrying phenomenon. Rotting wood loses its structural integrity and can lead to collapsing floors and walls if it is allowed to run rampant. You will recognize wood rot by changes in the color and texture of the wood around your home, in most cases. 

Health Concerns 

Alongside the fungal spores that cause wood rot around a home, there are fungal spores that present a more immediate danger to your health and well-being. Mold and mildew can be benign, but there are some forms that are incredibly toxic. Black mold can have a range of side effects from breathing difficulties and infections to fainting and seizures. The side effects you might experience depend on a number of things, including the severity and length of your exposure to the mold in your home. 

Those who are already vulnerable are at the most risk. Those who have underlying respiratory or auto-immune conditions like bronchitis, emphysema, and anemia are far more at risk of a serious reaction, alongside those receiving treatments for cancer, young children, and the elderly. For these people, prolonged or serious exposure to black mold could be very damaging indeed. In fact, it could be lethal. As such, it is important to act quickly when you see signs of mold. The most frequent problem signs of mold include a musty smell and patches of discoloration in areas that are often damp. If you see suspected mold formations, please do not touch them. 

Just because you have installed a crawl space door that is waterproof and weather-resistant, doesn’t mean you will never face issues within your crawl space again. A loose crawl space door can cause all kinds of problems in your home in a surprisingly short amount of time. 

Damage and Dampness 

One of the biggest issues with a loose crawl space door is how it can lead to increased dampness and humidity around your home. Even a small gap between your crawl space doors and entryways and their frames can allow water to seep in during storms, allow pests into your home, and even make it easier for intruders to gain entry to your home via your crawl space. 

This is worse than simply having an exposed gap in your property’s crawl space, because of how a partially affixed crawl space door traps moisture inside your crawl space. While the stack effect can cause many issues, it does keep the air moving. Without this, a damp crawl space becomes an incubator for moisture and fungal growth. 

Replacement and Repair 

Thankfully, a loose crawl space door or entryway is an easy thing to fix with the right help. A professional can easily assess the cause of the looseness and find a replacement door. If the issue is something smaller, however, like worn or damaged seals around the door, they can simply refresh the seals to prevent water from getting into your crawl space. 

This is a quick and low-cost process, but the damage that can spring from having a loose crawl space door for too long is more concerning. This is why it is important to check your crawl space doors and entryways at regular intervals. Act quickly if you notice that they are loose or the seal around them has become worn, cracked, or damaged in any way. 

AFS Offers Expert Waterproofing in Alabama and Tennessee 

If you think your crawl space may have issues with dampness and damage, or you are concerned about the health and well-being of your crawl space doors and entryways, your first call should be to AFS Foundation & Waterproofing Specialists. We have over two decades of experience in dealing with these issues and our experts ensure absolute confidence in our repairs. 

If you need some convincing, however, you can call us to arrange a free inspection appointment at your convenience. Alternatively, you can book your appointment online. These appointments come with a free written estimate for the cost of our suggested solutions and absolutely no obligation to book repairs through us on the day or at any time thereafter. We are happy to serve Birmingham, Huntsville, and Mobile, Alabama, and Nashville, Chattanooga, and Knoxville, Tennessee. 


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Birmingham, AL

130 Interstate Commerce Crt. Bldg. 100 & 200
Alabaster, AL 35007

Chattanooga, TN

214 Industrial Park Dr.
Soddy-Daisy, TN 37379

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2701 Opelika Road
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1909 Montgomery Hwy, Suite 322,
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118 E Mobile St
Florence, AL 35630

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2415 Jordan Road
Huntsville, AL 35811

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3028 E Governor John Sevier Highway
Knoxville, TN 37914

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